寫在前面:雖然看了很多網路上的資訊與討論，但是後來發現，這些資訊都是片面的，無法帶給我一個比較完整的架構，所以我決定直接閱讀原文，並且擷取我認為比較重要，且對台灣投資人來說比較攸關的資訊，給讀者朋友們做參考。
本篇內容將不定期更新與修正，直到整理完畢為止，如果發現我有撰寫錯誤，或是文句不通順的地方，還請不吝指教。
前言
PAGE1
Introduction
"For tax purposes, an alien is an individual who is not a U.S. citizen. Aliens are classified as nonresident aliens and resident aliens. This publication will help you determine your status and give you information you will need to file your U.S. tax return. Resident aliens generally are taxed on their worldwide income, the same as U.S. citizens. Nonresident aliens are taxed only on their income from sources within the United States and on certain income connected with the conduct of a trade or business in the United States."
一般來說，俗稱的外國人係指非美國公民。其可以分為非居住在美國的外國人以及居住在美國的外國人，居住在美國的外國人，針對其美國來源所得及非美國來源所得課稅，等同於美國公民；非居住在美國的外國人，僅針對下列兩種情形課稅:1.美國來源所得2.與美國境內貿易或商業有關聯的特定所得。
PAGE2
What's New
Personal exemption increased. "For tax years beginning in 2012, the personal exemp-tion amount is increased to $3,800. "
在2012年，個人免稅額增加至3,800美金。
PAGE3
Interest-related dividends and short-term capital gain dividends received from mutual funds. "The exemption from withholding on cer-tain interest-related dividends and short-term capital gain dividends paid by a mutual fund or other regulated investment company was scheduled to expire at the end of 2011. These provisions have been extended through 2013. "
特定與利息相關的股利及短期資本利得豁免預扣稅款的規定，原先優惠至2011年底，目前確定順延至2013年。
Chapter 1. Nonresident Alien or Resident Alien?(可參考這篇文章)
首先，你必須決定你的課稅身分，到底是居住在美國的外國人或是非居住在美國的外國人。居住在美國的外國人認定原則(二擇一):1.綠卡測試2.顯著居留測試；不符合上述條件者，皆視為非居住在美國的外國人。
Chapter 2. Source of Income
PAGE10
After you have determined your alien status, you must determine the source of your income.
在確認完課稅身分後，接下來你必須決定所得的來源。
Resident Aliens
A resident alien's income is generally subject to tax in the same manner as a U.S. citizen. If you are a resident alien, you must report all interest, dividends, wages, or other compensation for services, income from rental property or royal-ties, and other types of income on your U.S. tax return. You must report these amounts from sources within and outside the United States.
若你是居住在美國的外國人,那麼你所適用的稅率就跟一般的美國公民一樣,你必須申報所有美國來源所得及非美國來源所得。
Nonresident Aliens
A nonresident alien usually is subject to U.S. in-come tax only on U.S. source income. Under limited circumstances, certain foreign source in-come is subject to U.S. tax. See Foreign In-come in chapter 4.
一般來說，非居住在美國的外國人通常僅對美國來源所得課稅，但在特定情況下，外國來源所得也必須課稅，詳第4章。
Not all items of U.S. source income are taxable. See chapter 3.
並非所有的美國來源所得都要課稅，詳第3章。
Dividends
In most cases, dividend income received from domestic corporations is U.S. source income. Dividend income from foreign corporations is usually foreign source income. Exceptions to both of these rules are discussed below.
First exception. Dividends received from a domestic corporation are not U.S. source in-come if the corporation elects to take the Ameri-can Samoa economic development credit.
Second exception. Part of the dividends re-ceived from a foreign corporation is U.S. source income if 25% or more of its total gross income for the 3-year period ending with the close of its tax year preceding the declaration of dividends was effectively connected with a trade or busi-ness in the United States. If the corporation was formed less than 3 years before the declaration, use its total gross income from the time it was formed. Determine the part that is U.S. source income by multiplying the dividend by the fol-lowing fraction.
一般情況下，從國內公司所收到的股息為美國來源所得；從國外公司所收到的股息為國外來源所得，但是有例外，如下:
1.國內公司所配發的股息非屬美國來源所得—
2.國外公司所配發的股息屬美國來源所得—宣告股息前三年內，該公司營收超過25%與美國境內貿易或商業有關聯。
PAGE12
非居住在美國的外國人，收入來源認定總表(圖片可點擊放大):
Chapter 3. Exclusions From Gross Income
P
AGE14
Interest Income
Interest income that is not connected with a U.S. trade or business is excluded from income if it is from D
eposits (including certificates of deposit) with persons in the banking business
銀行存款利息與美國境內貿易或商業無關聯，故免稅。
PAGE15
Dividend Income
The following dividend income is exempt from the 30% tax.
Certain dividends paid by foreign corpora-tions. There is no 30% tax on U.S. source divi-dends you receive from a foreign corporation. See Second exception under Dividends in chapter 2 for how to figure the amount of U.S. source dividends.
Certain interest-related dividends. There is no 30% tax on interest-related dividends from sources within the United States that you re-ceive from a mutual fund or other regulated in-vestment company in 2012. The mutual fund will designate in writing which dividends are in-terest-related dividends.
Certain short-term capital gain dividends. There may not be any 30% tax on certain short-term capital gain dividends from sources within the United States that you receive from a mutual fund or other regulated investment com-pany. The mutual fund will designate in writing which dividends are short-term capital gain divi-dends. This tax relief will not apply to you if you are present in the United States for 183 days or more during your tax year.
下列股息免除30%稅率:
1.國外公司所配發的特定股息:國外公司所配發的股息屬美國來源所得—宣告股息前三年內，該公司營收超過25%與美國境內貿易或商業有關聯。
2.與利息相關的股息:基金將自行區分哪些是與利息相關的股息。
3.特定短期資本利得:基金將自行區分哪些是短期資本利得。例外，若你在該課稅年度內居住(留)滿183天，則不適用此規定。
Chapter 4. How Income of Aliens Is Taxed
PAGE16
Introduction
Resident and nonresident aliens are taxed in different ways. Resident aliens are generally taxed in the same way as U.S. citizens. Nonres-ident aliens are taxed based on the source of their income and whether or not their income is effectively connected with a U.S. trade or busi-ness.
居住在美國的外國人與非居住在美國的外國人，其課稅方式不同。前者與美國公民一樣，後者取決於收入的來源以及其收入是否與美國境內貿易或商業有關聯。
PAGE17
Nonresident Aliens
A nonresident alien's income that is subject to U.S. income tax must be divided into two cate-gories:
Income that is effectively connected with a trade or business in the United States, and Income that is not effectively connected with a trade or business in the United States (discussed under The 30% Tax, later).
The difference between these two catego-ries is that effectively connected income, after allowable deductions, is taxed at graduated rates. These are the same rates that apply to U.S. citizens and residents. Income that is not effectively connected is taxed at a flat 30% (or lower treaty) rate.
下列兩種情況下，非居住在美國的外國人適用美國的所得稅率:
1.與美國境內貿易或商業有關聯的所得(俗稱的ECI)
2.與美國境內貿易或商業無關聯的所得(俗稱的Non-ECI or NEC)
兩者之間的差別在於，前者有免稅額且適用累進稅率，其課稅方式同美國公民；後者則適用30%的單一稅率(若有稅務協定的話，會更低)。
Trading in stocks, securities, and commodi-ties. If your only U.S. business activity is trad-ing in stocks, securities, or commodities (includ-ing hedging transactions) through a U.S. resident broker or other agent, you are not en-gaged in a trade or business in the United States.
假如你在美國，除了透過美國本土的券商或機構進行股票及有價證券的投資之外，沒有額外活動的話，那麼就不算與美國境內貿易或商業有關聯。
In limited circumstances, some kinds of for-eign source income may be treated as effec-tively connected with a trade or business in the United States. For a discussion of these rules, see Foreign Income, later.
在某些特殊情況下，外國來源所得可能被認定為與美國境內貿易或商業有關聯，詳
Foreign Income。
待續...
免責聲明:文中所及之內容為作者自行閱讀Pub519刊物，而後撰寫完成，僅提供投資朋友們做參考，惟不保證其正確性，本部落格與IRS之間亦無任何利益往來，對此不負任何法律上之責任。
